Safety Interlock Pro Reference Manual
3/2020
Powering Up
After the Safety Interlock is installed, it is time to power it up and test that bumper switches, pressure
mats, and/or limit switches are working correctly. The Safety Interlock Pro requires 24VDC from the
showstopper circuit in order to receive power.
Signal Connections
The Stagehand controller sources 12VDC on a pin of each limit circuit and expects to see that 12VDC
signal returned on the other pin when the limit is not activated. If the limit is activated, disconnected,
or a wiring fault occurs, the 12VDC return signal is interrupted and the Stagehand Pro will enter a limit
fault condition and disallow motion.
Adding a safety interlock pro to a Stagehand Pro allows additional limit switches and safety sensors
to be monitored. These switches and sensors interrupt the forward, reverse, and ultimate limit circuits
coming from the machine.
The limit switch inputs are used to protect against the motor traveling too far in a direction and
causing damage or injury.
Limit Connections
The Stagehand Pro motion controller monitors forward, reverse, and ultimate limit circuits. The
auxiliary limit connections place additional limit connections in series with those already connected to
the Stagehand Pro.
Diving a little deeper into limit signals:
●
Ultimate Limit – a pair of switches can be wired in series to this pair of terminals to provide
protection against Forward and Reverse Limit switch failures. Traditionally, these switches are
wired Normally Closed (N.C.) but can different depending on the application. Typically, an
Ultimate Limit switch is positioned just beyond both the Forward and Reverse Limit switch. If
any Ultimate Limit is activated, the Stagehand will disallow any further movement until the limit
is physically cleared. An Ultimate Limit signal indicates an equipment problem with at least one
Page 6 of 10